[AnilG]

Supplicant does not seem to start or stay running when using the following /etc/rc.conf lines:

wlans_upgt0="wlan0"
wpa_supplicant_enable="YES"
ifconfig_wlan0="ssid thewirelessssid DHCP"

> ps aux | grep supplicant
<nothing>

But the following /etc/rc.conf does work:

wlans_upgt0="wlan0"
wpa_supplicant_enable="YES"
ifconfig_wlan0="ssid thewirelessssid"
ifconfig_wlan0="WPA SYNCDHCP"

Supplicant can be seen running with the following command line:
> ps aux | grep supplicant
/usr/sbin/wpa_supplicant -s -B -i wlan0 -c /etc/wpa_supplicant.conf -D bsd -P /var/run/wpa_s


I now get 'Associated' from ifconfig wlan0 as soon as I boot.
I'm very happy with that.
Thanks to every one for their help, especially shep.